No Definitive Evidence of Paleocene Dinosaurs in the San Juan Basin
- ASU Author/Contributor (non-ASU co-authors, if there are any, appear on document)
- Andrew B. Heckert Ph.D., Professor (Creator)
- Institution
- Appalachian State University (ASU )
- Web Site: https://library.appstate.edu/
Abstract: In a recent article in this journal, Fassett (2009) concludes that dinosaur fossils of
Paleocene age are present in the San Juan Basin of New Mexico-Colorado. However,
we argue that, based on existing data, Fassett has failed to produce compelling evidence
to support this conclusion. In the San Juan Basin, only one arguably reworked
dinosaur bone (an isolated hadrosaur femur) is stratigraphically above undisputed
Paleocene pollen, so palynology does not demonstrate Paleocene dinosaurs in the
San Juan Basin. Nor does magnetostratigraphy, because Fassett’s disregard of a
major unconformity above the dinosaur-bearing Naashoibito Member renders questionable
his use of an uninterrupted magnetostratigraphy to assign a Paleocene age to
dinosaur fossils in that unit. Moreover, Fassett’s article failed to adequately dismiss the
broadly held conclusions that: (1) the Cretaceous-Tertiary boundary is within the Ojo
Alamo Sandstone; (2) the dinosaur-dominated vertebrate fossil assemblage of the
lower Ojo Alamo Sandstone (Alamo Wash local fauna of the Naashoibito Member) is of
Maastrichtian age; and (3) the isolated, water-worn and/or fragmentary dinosaur bones
from the overlying Kimbeto Member are reworked from underlying Cretaceous strata.
No Definitive Evidence of Paleocene Dinosaurs in the San Juan Basin
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Additional Information
- Publication
- Lucas, S.G., Sullivan, R.M., Cather, S.M., Jasinski, S.E., Fowler, D.W., Heckert, A.B., Spielmann, J.A., and Hunt, A.P., (2009). No definitive evidence of Paleocene dinosaurs in the San Juan Basin. Palaeontologia Electronica, 12, p. 10 (ISSN: 1094-8074). Published by Coquina Press and available from the publisher open access at: http://www.palaeo-electronica.org/2009_2/199/index.html
- Language: English
- Date: 2009